Dual electronic counter



April 27, 1954 p. P. STIFF 2,676,755

DUAL ELECTRONIC COUNTER F iled Nov. 19, 1952 2 Sheets-Sheet 1 COO/V753 [wanton flaw/4 A0 5775 April 27, 1954 p, sT|FF 2,676,755

DUAL ELECTRONIC COUNTER Filed Nov. 19, 1952 2 Sheets-Sheet 2 Patented Apr. 27, 1954 DUAL ELECTRONIC COUNTER Daniel P. Stifi, Fairfield, Ala., assignor to United States Steel Corporation, a corporation of New Jersey Application November 19, 1952, Serial No. 321,404

4 Claims. 1

This invention relates to a dual electronic counter and more particularly to such a counter -or counting sheets which are to be transferred from a single path to two piles. In certain types of sheet stackers the sheets are discharged from a shearing line onto a narrow dead conveyor on either side of which are conveyors upon which the sheets are stacked by hand. Operators stand on each side of the dead conveyor and each sheet is pulled toward one or the other of the operators and placed on a pile. It is desired to count the number of the sheets in each pile.

It is therefore an object of my invention to provide a dual electronic counter by which sheets are removed transversely from their path of travel, piled in stacks on each side of the path of travel with the sheets in each pile being auto matically counted.

This and other objects will be more apparent after referring to the following specification and attached drawings, in which:

Figur 1 is a plan view of the apparatus with which the counter is associated;

Figure 2 is a side elevation of the apparatus of Figure 1;

Figure 3 is an enlarged plan View, showing part of the apparatus of Figure 1, with the position of the counter being indicated; and

Figure 4 is a schematic Wiring diagram of the counter.

Referring more particularly to Figures 1, 2 and 3 of the drawings, sheets S traveling over a conveyor 2 are delivered to a narrow dead roller conveyor l, commonly called a mill bar. Mounted below the mill bar 4 on each side thereof are roller conveyors 5 and 8. An operator stands at the side of each of the conveyors B and 8 and alternately removes sheets S from the mill bar 8. Located above the mill bar 4 is a light source it beneath which are mounted a. pair of phototubes l 2 and it. It will be noted that the phototubes l2 and M are mounted side by side transversely of the mill bar 4. The phototubeslZ and M are connected to a control unit It which operates the counters H3 and 20. The counters l8 and 26 may be of a standard electromagnetic type.

Referring to Figure 4, power for the photocells l2 and I4 and control unit I 6 is provided from 110 volt A. 0, power lines 22 and24. The lines 22 and 24 supply power to the primaries of transformers 26 and 28, the secondaries of which are connected to rectifier tubes 30 and 32, respectively, The cathodes of the-tubestt and 32 are connected to filters 34 and 36, respectively. The

a transformer 38 and two condensers eii connected to ground. The filter 36 consists of a similar transformer 42 and condensers 4 connected to ground. Alternating current for the circuit is taken from the secondary of transformer 26 by means of the wire it. The other side of the alternating current is connected to ground. A positive direct current is taken from the filter 34 by means of the Wire 48. A negative direct current is taken from the filter 35 by means of the wire 50. The other side of the direct current is connected to ground. Gther means than those described above may be used as the source of power. The wire 50 is connected to the cathodes of the phototubes I2 and Hi through a voltage divider consisting of resistors 52 and 5% which insures that the right potential is provided to the cathodes. Two electronic tubes as and 58 have their grids 56G and 586 connected to the anode of phototube I2. The cathodes 56C and 58C are connected to ground and the cathode 56C is connected to grid 55G through a resistor 60. Two electronic tubes 82 and 6 3 have their grids 62G and MG connected to the anode of phototube I4. The cathodes 62C and t t-C are connected to ground. The cathode 5 10 is connected to the grid 64G through resistor 55. A thyratron tube 68 has its grid 68G connected to the plate 5GP through resistors 10 and 12. The resistor It is connected to the wire 55 in series with a resistor 14 and to ground through a resistor 16. The plate ESP is connected to the wire t6 through the primary of-a transformer 73. A second thyratron tube has its grid 853G connected-to the plate 62F through resistors t2 and 84. Resistor 82 is connected to the line to in series with a resistor 86 and to ground in series with a resistor 88. The plate 89F is connected in parallel with the plate 68P to the line t5 through the primary or a transformer as. The cathodes 68C and 860 are con nected to ground through a, resistor 9|.

Dual vacuum tubestz and 94 are connected as a flip-flop or cuit. The grids eat; and MG are'connected in parallel to the wire 50 through resistors 96 and as, respectively, and to ground through resistors 56 and Hit, respectively. The plate MP is connected to grid 92G through resistor I04 and to plate 62? througs resistors I06 and H18 connected in series. Plate MP is connected to the plate 58F through resistors I68 and H0; Cathodes 532C and 3 55 are connected in parallel to ground through resistor H2. Plates 9 2? and 9d? are connected in parallel throughresistors filter 36 consists of trigger type multivibrator cir- 1 I I4 and IIS to the wire Mi. Plate 921 is connected to grid 94G through resistor H8.

Flow of current through counters Iii and 29 controlled by means of thyratron tubes I28 and I22, respectively, the counters being connected to the plates 52b? and I22P. The plates I20? and I22 are also connected to the wire 22 through capacitors I24 and I25, respectively. The cathode iZiiC is connected to the wire to through resistors I23 and I38 connected in senies. The cathode I220 connected to the wire 55 through resistors I28 and I3il connected in series. The grids IZBCT and IZZG are connected in parallel to plate 94 through capacitors I36 and I38, respectively. The grid 129G is connected to the plate I IDP of vacuum tube Hi through resistor I42. The grid IMG is connected to wire through resistors i213 and IM. One side of the secondary of transformer I8 is connected to the cathode M and the other side is connected to the grid MEG through resistor Md. The grid I22G is connected to the plate I45? of a vacuum tube M6 through resistor M8. The grid MSG is connected to wire 59 through resistors I32 and I58. One side of the secondary oi transformer so is connected to the cathode L6G the other side of the grid MSG through resistor iEci.

The operation of the counters is follows:

Assuming that there is light on the photocells I2 and I4 the resistance will be low and there will be negative voltage on the grids of tubes 62 and 64. The grids of these tubes will be most negative so that the tubes are biased beyond cutoff and will not conduct. Since tubes and G l are not conducting their plate voltage is high, thus causing the grid bias voltage of tube to be slightly positive so that it will conduct. Since tubes 92 and 94 are connected as a flip-flop multivibrator circuit the tube 94 will be cut off. The connections of thyratron tubes iii and Bi! are such that if one tube fires or conducts the other cannot. Assuming that the tube 63 is conducting there will be current flowing through the primary of transformer I8 and the voltage of the secondary of the transformer will be rectified by the tube I40 and introduced into the grid IZKBG of tube I29 as a high negative voltage so that tube I20 cannot conduct. Under the foregoing condi tions the grids of tubes I28 and I22 are biased from line i} so that they are not conducting.

When a sheet is delivered to the mill bar it over the photocells I2 and i4, light to the photocells It. and I4 will be out oif and the tubes 56, 58, 62 and 64 will all conduct. The plate voltage of the tubes 58 and B4 is low due to the drop in their common plate load resistor Hit and the bias on tube 92 will be negative, thus causing tube 82 to be out off and tube M to conduct. The plate voltage of tubes 56 and 62 is low which causes the tubes 68 and 30 to be biased beyond out off and no voltage is developed in the secondary of transformers I8 and 90. Therefore, tubes i2!) and I22 will be biased beyond out off. When tube 94 started to conduct a negative pulse was transmitted to the grids of tubes I28 I22 but with out causing any change in their operation.

Assuming that the sheet S is to be removed to conveyor 3 the photocell I2 will be uncovered while photocell I4 remains covered. Under these conditions the tube 56 will be cut oii thus causing a high positive voltage to be impressed on plate 55F which is transmitted through resistor 12 to grid BBGthus causing tube till to fire. The grid bias on the thyratron tube 68 is slightly positive when there is no light on the photocelh This tends to keep the gas ionized even though the plate potential is negative. The transformer in the plate circuit of tube 63 contains considerable inductance. This inductance and the fact that the grid is slightly positive tends to keep the current flowing during the negative cycle of the plate potential. This produces a voltage in the secondary of transformer 18 which is fied by tube I40 and is developed across resistor I44. This produces a high negative voltage which is applied to the grid IZOG. Tube 553 is cut off at the same time tube 55 is cut off, but the platvoltage of tube 58 does not change appreciably due to its common plate load resistor its and since tube 64 is still conducting the voltage resistor I96 does not change enough to cause tube $12 to conduct. Therefore, tube is still conducting and tube 92 out off and no pulse is transmitted to the grids of tubes I25 and lit.

Removal of the sheet S to the conveyor it uncovers the photocell I4 and the tube 5'2 is cut oif with no effect since tube is locked out by tube (28. Tube 64 is out oif and its plate voltage is raised causing tube 92 to conduct and tube t l to be cut off. When tube is is cut it transmits a sharp positive pulse to the grids of tubes and I22 through the coupling condensers list and i338. This has no eifect on tube I20 since the volt age rectified by tube I40 has a greater negative value than the positive pulse can overcome. However, the pulse is suflicient to overcome the grid bias of tube I22 causing it to conduct n1o mentarily and operate the counter 28. The circuit is now ready to receive another sheet 5 which will cover both phototubes with the same result as above. Assuming that the second sheet is to be pulled. oii in the opposite direction so that phototube Hi is uncovered first, the tube 64 will be cut off with no effect and tube 62 will be cut oil raising its plate voltage and causing tube 60 to fire. The voltage developed in the secondary of plate transformer is rectified by tube I46 and introduced as a high negative voltage across resistor Ibti to the grid circuit of tube I22. Therefore, tube I22 will not be able to fire even with a positive pulse from tube 94. Tube 92 will be out off and tube 34 will be conducting.

When a sheet is removed completely from the mill bar 1 there Will be light on both phototubes and the positive voltage of tube 58 will be raised causing the flip-flop of tubes 92 and 94 to send a positive pulse to the grids of tubes I25! and I22. This pulse has no effect on tube I22 but will cause tube I2Il to conduct and operate th counter Ill.

The above operations will be repeated each time a sheet is received over the photocells I2 and It and removed in one direction or the other.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1.. In apparatus wherein traveling sheets or the like are removed transversely from their path of travel in two directions, a pair of'count ore for separately and automatically counting the sheets removed in each direction, a pair of photocells arranged transversely of the path of travel of said sheets on one side of said sheets, a light source on the other side of said sheets, a first thyratron tube, a second thyratron tube, one of said counters being in the plate circuit of the first thyratron tube and the other of said counters being in the plate circuit of the second thyratron tube, a first and second tube each having its rid connected to the anode of the first of said photocells, said first and second tubes being adapted to fire only when light is not on the first photocell, a third and fourth tube each having its grid connected to the anode of the second of said photocells, said third and fourth tubes being adapted to fire only when light is not on the second photocell, means connected to said four tubes for providing a high negativ voltage on the grid the first thyratron tube when a sheet covering both photocells is removed from the first photocell, and means responsive to the uncovering of the remaining photocell for applying a positive pulse on the grids of the thyratron tubes whereby the tube without the negative pulse thereon will conduct and the other tube will not.

2. In apparatus wherein traveling sheets or the like are removed transversely from their path of travel in two directions, a pair of counters for separately and automatically counting the sheets removed in each direction, a pair of photocells arranged transversely of the path of travel of said sheets on one side of said sheets, a light 9 source on the other side of said sheets, a first thyratron tube, a second thyratron tube, one of said counters being in the plate circuit of the i'st thyratron tub and the other of said counttron tube, a first and second tube each having its rid connected to the anode of the first of said photocells, said first and second tubes being adapted to fire only when light is not on the first photocell, a thircland fourth tube each having its grid connected to the anode of the second of said photocells, said third and fourth tubes being adapted to fire only when light is not on the second photocell, means connected to said four tubes for providing a high negative voltage on the grid of the second thyratron tube when a sheet covering both photocells is removed from the secth remaining photocell for applying a positive pulse on the grids of the thyratron tubes where by the tube without the negative pulse thereon will conduct and the othetube will not.

In apparatus wherein traveiing sheets or the like are removed transversely from their path of travel in two directions, a pair of counters for separately and automatically counting the sheets removed in each direction, a, pair of photochls arranged transversely of the path of travel of said sheets on one side of said sheets, a light source on the other side of said sheets, a first and second tube each having its grid connected to the anode of the first of said photocells, said first and second tubes being adapted to fir only when not on the first photocell, a third and fourth tube each having its grid connected to the anode of the second of said photocells, said hird and fourth tubes being adapted to fire only when light is not on the second photocell, electrical connections between the plates of said tubes, 2, first thyratron tube, an electrical connection betweenthe .plate of the first. tube and the grid ofit e first. thyratron tube, a second source on the other side of said sheets, a first and second tube each haVing its grid connected to the anode of the first of said photocells, said first and second tubes being adapted to fire only when firing, the second thyratron tube starting to fire when the third and fourth tubes are cut off and the first and second tubes are firing, an electrical connection between the plate of the third said thyratron tubes, a first transformer having its primary in the plate circuit of the first thyratron tube, a second transformer having its primary in the plate circuit of the second thyratron tube, a fifth tube having its cathode connected to one side of the secondary of the first transformer, a sixth tube having its cathode connected to one side of the secondary of the second transformer, a third thyratron tube having its cathode connected to the other side of the secondary of the first transformer, said third thyratron tube having a high negative voltage applied to its grid when current flows through the first transformer, a fourth thyratron tube having its cathode connected to the other side of the secondary of the second transformer, said fourth thyratron tube having a high negative voltage applied to its grid when current flows through the second transformer, an electrical connection between the plate of the fifth tube and grid of the third thyratron tube, an electrical connection between the plate of the sixth tube and grid of the fourth thyratron tube, one of said counters being in the plate circuit of each of said third and fourth thyratron tubes, a flip-flop circuit comprising a seventh and an eighth tube, an electrical connection between the plate of th seventh tube and grid of the eighth tube, an electrical connection between the grid of the seventh tube and plate of the fourth tube, an electrical connection including a capacitor between the plate of the eighth tube and grid of the third thyratron tube, and an electrical connection including a capacitor between the plate of the eighth tube and grid of the fourth thyratron tube, said eighth tube being adapted to fire when the first four tubes are conducting and to be cut off when the first four tubes are cut off, said fourth thyratron tube firing when said eighth tube is out off and said first thyratron tube is firing, said third thyratron tube firing when said seventh tube is cut off and said second thyratron tube is firing.

References Cited in the file of this patent UNITED STATES PATENTS 

